Change Page: < 1234 > | Showing page 2 of 4, messages 21 to 40 of 71 - powered by ASPPlayground.NET Forum Trial Version
Reports tied to this Journal
Author
|
Message
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Saturday, January 26, 2013 8:53 AM
( permalink)
Jim, this is an excellent communication of your work. It's the kind of thing we need to understand how to manage these live foods well. Please continue!
check out Kathy's Clowns, llc website: http://kathysclowns.com Captive bred clownfish and more (Wholesale to the trade.)
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, January 27, 2013 1:33 AM
( permalink)
The more I keep Googling different search phrases related to algal densities and the cultivation of copepods, two trends emerge. First, while the best results seem to almost always be achieved with a mixture of different algae, the overall best performing single algae is Isochrysis galbana. Second, the clear consensus is that an Isochrysis cell density of somewhere between 10,000 and 100,000 cells per ml is almost always used. That said, I did run across an interesting paper, "Development of aquaculture technology for the flame angelfish, Centropyge loriculus" by Laidley, et. al., 2008. Aside from having a lot of interesting stuff about breeding flame angels, it also discusses their efforts to improve their Parvocalanus culture protocols. It says, "We are continuing to refine culture conditions having optimized feed density (~300,000 cells/ml), temperature (~25ºC), photoperiod (little effect), salinity (22ppt) and culture density (~1/ml)...." This paper also confirms that high densities of adult Parvocalanus results in reduced reproductive activity. My idea of trying to come up with an easy colorimetric method for approximating cell density at these relatively low levels has some mixed results. For those of you already familiar with the Merck D-D Phosphate test kit, please bear with me here. I have said test kit, and I really like it. Unfortunately, it is no longer available in the USA. It does a very good job of detecting relatively low levels of phosphate. Like many aquarium test kits, it colorimetric in nature. Detecting phosphate at low enough levels to be meaningful to the reefkeeper isn't easy, but this test kit does the trick, IMHO. It uses a pair of glass vials, each of which holds 20 ml of tank water, that rest in a black styrofoam holder with two holes drilled through it to accommodate the two vials. Here is a picture of the kit, where you can see the vials and the styrofoam holder on the right, and also a picture of the color comparison chart: The idea is that one vial holds untested tank water, and the other holds the water that has undergone a color change due to the test. You then place the vials, encased in the black styrofoam, over the color chart, with the untreated water over the colorized circles, and the treated water over the plain white circles. When the color of both vials matches when looking down through them at the color chart, you have determined the amount of phosphate. The black styrofoam helps to avoid having the color of nearby objects interfere with the subtle color difference perception necessary to achieve the desired resolution with this test kit. My idea was to see if I could re-purpose the D-D Merck vials and black styrofoam holder, while making up my own color chart, that would be able to detect phytoplankton density in the range I'm working with in the Parvocalanus culture. The "mixed" results I got are as follows: The good news is that a density of 300,000 cells/ml is very much detectable with this method, and a density of perhaps 100,000 might be, but a density of more like 75,000 is very, very difficult to detect with this equipment. To give you an idea, here is the preliminary color chart I have come up with: The 300,000 cells/ml sample corresponds with the 6th color sample from the left. A 100,000 cells/ml sample corresponds with somewhere between the 4th and 5th sample from the left. The 75,000 sample is maybe the 2nd from the left, but it is VERY hard to tell. Perhaps if I leveraged this concept, but worked with taller vials, I'd be able to get better resolution. I'm not giving up on this idea just yet!
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, January 27, 2013 10:01 AM
( permalink)
Jim, Great information, and thanks for the pictures of the test kits. I've got something to compare results now to! Thank you.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, January 27, 2013 12:30 PM
( permalink)
Jim, based off of your approx 15M cells per mL, what kind of variance should you see based off of what Gresh is saying?
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, January 27, 2013 2:23 PM
( permalink)
I don't know, because Gresham didn't specify how great the variation might be. Well, that and a whole lot of other things I don't know! I hypothesize that as long as a measurement method that is based in Beer's Law is used, like a Secchi stick or a color/turbidity comparator such as I am suggesting, then the net approximate carbon content per liter would remain relatively constant as cell size grew or shrank, for the same species of microalgae. For example, lets take the combined Secchi stick reading, hemocytometer reading, and cell measurements I noted earlier as a starting off point. The Secchi stick and the hemocytometer both estimate 15,000,000 cells / ml, and the average cell size was 4.36 microns wide by 6.37 microns long. As noted above, that cell size (cell volume of 63 cubic microns) gives a value of 19.7 pg of Carbon per cell, which, when multiplied by the 15,000,000 cells in my Iso culture, gives appx. 300 micrograms of carbon per ml. Now, let's assume that the amount of variation in the cell size is +/- 20%. For cells that are 20% greater in both dimensions, the cell volume goes up to 109 cubic microns, and the resulting Carbon per cell goes up to 31.5 pg, and for cells that are 20% smaller in both dimensions, we get 32 cubic microns and 11.1 pg. I would not be at all surprised that, assuming the same Secchi stick reading for all the cultures (3.5 cm), the actual number of cells in the culture with the larger cells would be porportionally fewer, and the number of cells in the culture with the smaller cells would be porportionally greater. The Beer-Lambert law almost requires this to be true. Note also that the change in cell size does not affect the carbon content linearly. Cells 20% greater in both dimensions have 1.73 times the volume, and cells 20% smaller in both dimensions have 0.51 times the volume, while the larger cells have only 1.60 times the carbon, and the smaller cells have 0.56 times the carbon. In other words, larger cells tend to be less carbon dense, and smaller cells tend to be more carbon dense. This carbon density almost certainly will translate into opacity, which will directly affect the Secchi reading. In other words, again assuming a constant 3.5 cm Secchi stick reading for all the cultures, the one with the larger cells will need to have something like 15,000,000 / 1.73 = 8,670,000 cells per ml to account for the difference in volume, but then that value will need to be adjusted back up by a factor of 1.73 / 1.60 to account for the lower carbon density, for a final value of something like 9,400,000. Smaller cell culture computation is something like 15,000,000 / 0.51 * (0.51 / 0.56) = appx. 26,800,000. Now, I am probably oversimplifying the math, but if you've followed along, hopefully, you get the idea, which is this: For a given species of algae, the Secchi stick reading can probably be seen as a reading of carbon content, regardless of variation in actual cell size and count. At least, that is the assumption I am going to bring into the fish room with me until I get information convincing me otherwise. Again, this all needs to be considered in the context of the fact that we are using a very inexact measurement tool, and the precision required to get the job done.
<message edited by JimWelsh on Monday, January 28, 2013 3:36 AM>
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, February 3, 2013 1:12 AM
( permalink)
It has now been 25 days since I established the culture(s) of Parvo, and they are all doing very well. My two biggest problems are having to feed them at least twice daily in order to keep the algae from clearing, and having to split them when the density gets too great. I have good news / bad news on the "quantification of the amount of algae in the cultures" front. The bad news is, I really don't think I will be able to come up with any easy color-chart based method of determining algae density at the low levels we are working with here. The good news is that, with just a little bit of practice, it appears that it is very quick and easy to check the algal density using a hemocytometer and a microscope! That said, I will comment that I have not yet had any success at being able to see the hemocytometer grid in order to count the algae cells when using my Celestron digital microscope. In order to be able to successfully use the hemocytometer, I have had to use my conventional optical compound microscope, so far.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Sunday, February 3, 2013 2:49 PM
( permalink)
The major learning for me is that the optimal algal food concentration is so much lower than I've been thinking it should be. It makes sense, though, and also the more frequent feedings. My rotifers have been very productive since I put a perstaltic feeding pump on them, and the marinebio-guy has a continuous system that works well for him. When I try the parvocalanus, I'll put a peri feeding pump on them as well.
check out Kathy's Clowns, llc website: http://kathysclowns.com Captive bred clownfish and more (Wholesale to the trade.)
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Tuesday, February 12, 2013 3:26 AM
( permalink)
I'm well over a month now with these cultures, and they continue to do well for me. I am splitting them regularly, when they get "too dense", based on my casual observation. I have yet to actually quantify this density, but I estimate it to be somewhere between 1 and 5 adults per ml. When I split, sometimes I harvest the largest copepods, sieving the culture through an 80 micron mesh, which allows the smallest nauplii to pass through the sieve. I then return the sieved water back into the culture, and backwash the harvested copepods into a larval tank. Other times, it is an actual "split", where I take appx. 1/2 of the water in the culture, and transfer that into a new culture, and then double the volume of both cultures with new salt water (e.g., I split 1 x 2 liter culture into 2 x 2 liter containers, and add 1 x 1 liter of new salt water to each, to bring each culture up to a total of 2 liters). Sometimes, rather than splitting into a second culture, I simply feed the split portion to my 210 display tank. I have also gradually been bringing the salinity of the cultures down to 22 PPT, per Laidley, et. al., 2008, cited earlier in this topic.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 14, 2013 2:34 AM
( permalink)
One other note: I have noticed a definite trend: My cultures of this copepod generally tend to have either (A) a relatively large number of larger copepodites and/or adults, and relatively few nauplii and/or smaller copepodites, or (B) a relatively large number of nauplii and/or smaller copepodites, and relatively few adults and/or larger copepodites. It almost seems as though each culture cycles back and forth between the (A) state and the (B) state over time.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 14, 2013 9:22 AM
( permalink)
I have to admit, you are making me awfully curious about whether I just used too much algae paste in my attempts with these. I may just have to give them another shot when I get everything back up and running this summer. (I broke all my cultures down yesterday. I was a little sad, actually, since I'd kept them going so long.)
--Andy, the bucket man. "Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 14, 2013 1:17 PM
( permalink)
Yeah, I was thinking of trying to work with some very light paste doses with these guys, but the only algae paste I have that isn't Nanochloropsis-based is some very old, expired Shellfish Diet. It would be fun to try SDaquarist on them, though .
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 14, 2013 2:07 PM
( permalink)
Yeah. The Tet is awfully large and would maybe go uneaten, fouling the container, but the Iso and Pav would be a good place to start. Yeah, I think I might just add a bottle of that into the order when I re-start.
--Andy, the bucket man. "Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 14, 2013 2:35 PM
( permalink)
Actually, the paper, "Egg production, egg hatching success and population increase of the tropical paracalanid copepod, Bestiolina similis (Calanoida: Paracalanidae) fed different microalgal diets" Caymus, et.al, 2009, found here: http://bit.ly/TkgYZY shows that the best results for Bestiolina similis were with a mixture of Isochrysis, Pavlova, and Tetraselmis. I realize that Bestiolina is a little larger than Parvocalanus, but not that much larger, and they are quite closely related, so I would expect similar results with Parvocalanus.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 11:32 AM
( permalink)
Jim, question for you. I'm going to try and culture this. In The Use of Calanoid Copepods in Semi-Intensive, Tropical Marine Fish Larviculture by Glenn Schipp, nutricionacuicola.uanl.mx/numeros/8/6Schipp.pdf, he talked about how he raised his copepods on a mixture of Isochrysis and Rhodomonas. Do you know if the Rhodomonas is necessary for culturing Parvo?
<message edited by Amphispur on Wednesday, February 20, 2013 11:44 AM>
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 12:02 PM
( permalink)
Rhodomonas is not necessary. I'm using a mixture of Isochrysis and Pavlova (Monochrysis), but I'm sure that Isochrysis alone would work, based on the results published by Caymus, et.al., 2009 "Egg production, egg hatching success and population increase of the tropical paracalanid copepod, Bestiolina similis (Calanoida: Paracalanidae) fed different microalgal diets" which you can read here: http://bit.ly/TkgYZY
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 2:11 PM
( permalink)
Very interesting information here Jim! Thanks for sharing so much. The test kit idea is brilliant, and I think you're onto something. Taller vials is probably what you're needing to make it easier to see the differences.
Don't let fear and common sense stop you! =]
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 6:30 PM
( permalink)
With reference to the Val. day conversation: Thanks for the paper, Jim. I'm excited to get cracking.
--Andy, the bucket man. "Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 7:32 PM
( permalink)
Not to pop your bubble, Andy, but Karen Brittain sent me the following link today: http://www.youtube.com/watch?v=NluJ43lUM4M There are many interesting things to be learned from watching the entire video, but the #1 take home points relevant to this topic are: 1) Parvocalanus crassirostris can be successfully raised for long periods of time using artificial seawater. 2) Optimum salinity for P. crassirostris is 30 PPT or greater. 3) Live Isochrysis worked well as a feed for P. crassirostris. Live Chaetoceros was not a good feed for P. crassirostris. 4) All manner of algae paste (Isochrysis, Tetraselmis, Nannochloropsis) were entirely unsuitable as feeds for P. crassirostris.
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Wednesday, February 20, 2013 7:42 PM
( permalink)
Dang. You are such a bubble popper. No worries. Saves me time, trouble, and money. Dang it, though.
--Andy, the bucket man. "Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886
|
|
Re:Culture Journal, Species: Parvocalanus crassirostris
Thursday, February 21, 2013 8:52 PM
( permalink)
I started cultures of isochrysis today... 30 ppt.
check out Kathy's Clowns, llc website: http://kathysclowns.com Captive bred clownfish and more (Wholesale to the trade.)
|
|
|